<div dir="ltr"><div>Hello,</div><div> </div><div>Yes, the next step for this compression scheme is to make it adaptive, more rle for plain regions, more differential coding for high contrast.I could start for example by decomposing the wavelet DC image in 16x16 blocks and giving 4 modes to each block: 1) plain (blank) block, more RLE, 2) high contrast, edges, more differential coding, 3) mid, current scheme, 4) texture, grain.As in the current state this scheme gives pretty good results on wavelet DC parts, this could be even better.</div><div> </div><div>Else, I'm slowly working again on the NHW codec.I would like to code the lower quality settings (-l3 and below, high compression) but it seems hard with my algorithm and HEVC intra is doing very well in this domain.On the contrary, for mid/normal compression (-l2 to -h3 setting), I prefer the NHW codec to HEVC because it has more neatness, I also prefer in this range Daala codec because of its grain and precision.</div><div> </div><div>Would it be possible to create a codec only for mid/normal compression (and upper quality)? Is there a niche for this kind of codec? My codec will be still royalty-free and very fast.</div><div> </div><div>Cheers,</div><div>Raphael</div></div><div class="gmail_extra"><br><div class="gmail_quote">2015-01-23 18:31 GMT+01:00 Raphael Canut <span dir="ltr"><<a href="mailto:nhwcodec@gmail.com" target="_blank">nhwcodec@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Hello,</div><div> </div><div>So here is the compression scheme that I don't know if is covered by patent.</div><div> </div><div>I use it on the wavelet DC parts.It outputs 1 byte (8 bits) words.There is 5 modes:</div><div> </div><div>- 1(MSB) | 7 bits to store value (0->127 range)</div><div>- 01 | 6 bits to store val[n+1]-val[n] | val[n]-val[n-1] if each in the range [-4,4]</div><div>- 001 | 5 bits to store val[n+2]-val[n+1] | val[n+1]-val[n] | val[n]-val[n-1] if each in range</div><div>- 0001 | special case</div><div>- 0000 | 4 bits for RLE+prediction</div><div> </div><div>It is a simple compression scheme, it is not as good as context modeling + arithmetic coding, but it gives good results on my data (wavelet DC parts) and is very fast.</div><div> </div><div>My question is: Does someone know if this compression scheme is patented?</div><div>Also, as it is quite simple, maybe the patent has expired (more than 20 year old)?</div><div> </div><div>Also, if someone knows a better compression scheme for DC parts (not too complex, I don't want to use context modeling + arithmetic coding for now, even if I know that patents on arithmetic coding have nearly all expired), do not hesitate to let me know.</div><div> </div><div>Cheers,</div><div>Raphael</div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">2015-01-18 10:02 GMT+01:00 Raphael Canut <span dir="ltr"><<a href="mailto:nhwcodec@gmail.com" target="_blank">nhwcodec@gmail.com</a>></span>:<br><blockquote style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class="gmail_quote"><div dir="ltr"><div>Hello,</div><div> </div><div>Ok, and that's too many work to review a source code.In my codec, I have 3 compression schemes, I think 2 are not patented, but the third... I don't know.For the rest, I think my codec is patent-free (I don't use SPIHT,EZW,zerotree methods), even the wavelet transform is new and don't use the lifting scheme nor the convolution product.</div><div> </div><div>Else, if you found time to review the codec, do not hesitate to let me know what you think of it and if you would have remarks.Would be much appreciated.</div><div> </div><div>Cheers,</div><div>Raphael</div></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">2015-01-17 23:01 GMT+01:00 Basil Mohamed Gohar <span dir="ltr"><<a href="mailto:basilgohar@librevideo.org" target="_blank">basilgohar@librevideo.org</a>></span>:<br><blockquote style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class="gmail_quote"><span>On 01/15/2015 12:39 PM, Raphael Canut wrote:<br>
> Hello,<br>
><br>
> Yes, that's right.I still think that it would have more weight if I<br>
> could claim that Xiph has reviewed the source code and find that the NHW<br>
> codec is royalty/patent-free (better than me alone claiming<br>
> this...).Maybe it was in this sense that Ralph Giles answered me?<br>
><br>
> Cheers,<br>
> Raphael<br>
</span>That's not a guarantee that anyone can make, not even a patent attorney. The current landscape is such that "being clear of patent concerns" is impossible. Someone can be destroyed by the legal process that results in them being exonerated, but then left with no will nor resources to continue development.<br>
<br>
I don't say this to scare you away, just understand that asking Xiph to "clear" the patent issues doesn't make sense. Xiph is a non-profit organization that advances the cause of free, open, and royalty-free technologies, but cannot offer a technically legal service as requested.<br>
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